This invention relates generally to novel polysaccharide polymers and methods for the production thereof. More particularly, it relates to a class of new polysaccharide polymers which are produced microbiologically from the action of certain bacteria on carbohydrate substrates.
It is known that polysaccharides are produced by the action of certain microorganisms on certain carbohydrates. Thus see Halleck et al 3,301,848 issued Jan. 31, 1967 "Polysaccharides And Methods For Production Thereof". It has now been discovered that certain bacteria of the genus Cellulomonas will produce a very novel and potentially highly useful polysaccharide polymer when incubated in a medium containing carbohydrate source materials. In general, this new class of polysaccharide polymers is characterized by a multiplicity of D-glucose units attached together in a straight chain through B-1,3 linkages.
All of the known Cellulomonas species (those available from deposit) will produce this polymer to a greater or lesser degree under like conditions.
One of the important advantages of the invention resides in the ability of the organisms listed above to produce the said polysaccharide polymer from a plurality of carbohydrate sources. For example, Cellulomonas flavigena 819 will produce a polysaccharide polymer from certain selected carbohydrate source materials selected from the group consisting of at least glycerol, glucose, galactose, fructose, sucrose, lactose, starch, and molasses.
A gelable B-1,3 glucan type polysaccharide is made by the aerobic cultivation of certain microorganisms. In some ways, this polymer generally resembles a known (thermally) gelable B-1,3, glucan known as "curdlan", but differs therefrom in certain other ways.
This invention relates to a new gelable polysaccharide polymer designated as Cellulomonas flavigena PS 819" or "PS 819" or "Cf/PS 819". More particularly, the invention is concerned with a microbial production of the polymer Cf/PS 819, with the polymer Cf/PS 819 as a new composition of matter exhibiting specific characteristics as well as having many potential applications.
It has been known that a thermally gelable B-1, 3 glucan named "curdlan" is produced by cultivation of a microbial mutant (strain K) of Alcaligenes faecalisvar. myxogenes 10C 3 (see Agricultural Biological Chemistry, volume 30, pages 196 et seq, 1966, by Harada et al). Additionally, see Kimura U.S. Pat. No. 3,822,250, issued Jul. 2, 1974 "Thermo-Gelable Polysaccharide" wherein the inventors found that a mutant (strain NTK-u) of the said strain K can also produce a thermally gelable B-1, 3 glucan type polysaccharide giving a new thermo-gelable polysaccharide designated as "PS". It was also shown that other microorganisms such as Agrobacterium radiobacter can also produce such new PS polysaccharide with substantially the same physico-chemical properties.
A principal object of the present invention is, therefor, to provide the newly found, gelable polysaccharide polymer Cf/PS 819.
Another object of this invention is to provide methods for producing polymer Cf/PS 819 by means of cultivation of a microorganism and subsequent purification of the product thereof.
Another object of the invention is to provide a new and useful polysaccharide polymer, as well as the process for its production, such polymer being synthesized by certain gram-positive, rod shaped bacteria (genus Cellulomonas) when they are cultured aerobically in a minimal salts medium containing a variety of carbohydrates and/or polysaccharides as carbon and energy sources.
Yet another object of the invention is to provide such a new glucan-type polysaccharide polymer that is synthesized by such microorganism and typically deposited externally thereof as a capsule about the bacteria.
The present invention relates to the production of a new and useful polysaccharide polymer by the treatment of the glucan type polysaccharide polymer that is synthesized and deposited (either externally as a capsule about the bacteria or internally as a granule within the bacteria) by a microorganism of the type Cellulomonas when cultured aerobically in a minimal salts medium containing a variety of carbohydrates and/or polysaccharides as carbon and energy sources, by treating the said cultured, extracted cells with specific solubilizing agents and subsequently removing said solubilizing agents by neutralization or water addition to affect gelation.
The present invention is based on the following observations:
(1) That microorganisms isolated from decaying leaf litter have an ability for producing a polysaccharide polymer able to form a gel;
(2) That said microorganisms belong to the genus Cellulomonas;
(3) That the polysaccharide polymer is synthesized and deposited externally as a capsule about the bacteria (or as a granule in the interior of the bacteria);
(4) That such polymer is synthesized by certain gram-positive, rod shaped bacteria (genus Cellulomonas) when such are cultured aerobically in a minimal salts medium containing a variety of carbohydrates and/or polysaccharides as carbon and energy sources;
(5) That said polymer may be extracted from the said Cellulomonas bacteria cells;
(6) That the recovered polysaccharide polymer has the property of forming a gel under defined conditions, as well as being repeatably solubilized and gelled.
Thus, according to the present invention, a polysaccharide polymer characterized by gel formation can be produced by cultivating a polysaccharide-polymer-having-gel-forming property-producing-microorganism belonging to the genus Cellulomonas in a medium containing assimilable carbon sources and nitrogen sources until said polysaccharide polymer is substantially accumulated within or about the cells of said culture, such accumulation perhaps causing and at least associated with aggregation of the cells of the culture, and thereafter recovering the accumulated polysaccharide polymer from said cells.